1. Field of the Invention
The present invention relates to a method of manufacturing a liquid-jet head, and to a liquid-jet head. Specifically, the present invention relates to a method of manufacturing an inkjet recording head which ejects ink as a liquid, and to a liquid-jet head.
2. Description of the Prior Art
An inkjet recording head with the following configuration is among inkjet recording heads which are used as liquid-jet heads (see Japanese Patent Laid-open Official Gazette No. 2003-159801, for example). Such an inkjet recording head includes a passage-forming substrate, piezoelectric elements and a reservoir forming plate. In the passage-forming substrate, pressure generating chambers and a communicating portion are formed. The pressure generating chambers communicates respectively with nozzle orifices, and the communicating portion communicates with these pressure generating chambers. The piezoelectric elements are formed over one side of this passage-forming substrate. The reservoir forming plate is joined to a surface of the passage-forming substrate, over which surface the piezoelectric elements are formed. The reservoir forming plate includes a reservoir portion which, along with the communicating portion, constitutes a reservoir. The reservoir is formed by causing the reservoir portion and the communicating portion to communicate with each other via a penetrating portion which penetrates through a vibration plate and a laminated film provided to the top of the vibration plate. Specifically, parts respectively of the vibration plate and the laminated film, which face the communicating portion (reservoir portion), are punched out mechanically. Thus, the reservoir portion and the communicating portion are caused to communicate with each other.
However, when the penetrating portion is formed by means of such a mechanical process, extraneous matter such as scraps is produced, and the extraneous matter goes into passages such as the pressure generating chambers. As a result, the mechanical process brings about a problem that the extraneous matter presents a cause of failure in ejection. Incidentally, if the penetrating portion is caused to undergo, for example, a cleaning process or the like immediately after the penetrating portion is formed, extraneous matter such as scraps can be removed to some extent, but it is still difficult to remove the extraneous matter completely. In addition, the mechanical process of forming the penetrating portion produces cracks and the like around the penetrating portion. This also brings about a problem that the production of cracks causes failure in ejection. Specifically, if ink is filled and ejected from the nozzle orifices while such cracks are left as they are, fragments are detached from cracked parts, these fragments clog up nozzle orifices. As a result, the mechanical process brings about a problem that the clogging causes failure in ejection.
Patent Document, which has been mentioned above, has disclosed a structure for preventing such extraneous matter from being produced by fixing the laminated layer with a coating film made of a resin material for the purpose of solving such problems. Adoption of this structure may check extraneous matter from being produced to some extent, but it is still difficult to completely prevent failure in ejection from stemming from the extraneous matter.
Moreover, in general, protection films made of a material reservoir and the like, which have been formed in the aforementioned manner, for the purpose of prevent the passage-forming substrate and the like from being eroded by the ink. In a case where such protection films are formed in the structure provided with the aforementioned coating film, part of the protection film is also formed on the top of the coating film. In addition, the part of the protection film which has been formed on the top of the coating film made of a resin material is poor at adhesion to a resin material, and accordingly is easy to come off from the coating film. Part of the protection film which has come off from the coating film is likely to clog up nozzles or cause similar problems.
It should be noted that occurrence of such problems is not limited to the method of manufacturing inkjet recording head which eject ink. It goes without saying that such problems also occur in a method of manufacturing other liquid-jet head which eject liquids other than ink.